• Macromolecular Research
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• 제8권1호
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• pp.1-5
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• 2000

The valiclity of the simple mathematical model for facilitated transport in a solid state membrane developed previously has been examined againsts the carrier concentration and membrane thick-ness. Membranes are prepared with copolymer of styrene and 4-vinylpyridine as a matrix and Co(salen) as a carrier. 4-Vinylpyridine is incorporated to provide the coordination site for Co(salen) carrier. Oxygen permeability through the facilitated transport membrane is linearly increased with the square of its thick-ness, as predicted by the mathematical model. However, the oxygen permeability does not increase linearly with the carrier concentration. This seems to be due to the deactivation of the carrier by dimerization at high carrier concentrations as well as the reduced chain mobility by coordination of bulky Co(salen) carrier.

• 대한전자공학회논문지SD
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• 제40권9호
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• pp.638-643
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• 2003

Channel width dependence of hot-carrier effect in nMOSFET with shallow trench isolation is analyzed. $I_{sub}$- $V_{G}$ and $\Delta$ $I_{ㅇ}$ measurement data show that MOSFETs with narrow channel-width are more susceptible to the hot-carrier degradation than MOSFETs with wide channel-width. By analysing $I_{sub}$/ $I_{D}$, linear $I_{D}$- $V_{G}$ characteristics, thicker oxide-thickness at the STI edge is identified as the reason for the channel-width dependent hot-carrier degradation. Using the charge-pumping method, $N_{it}$ generation due to the drain avalanche hot-carrier (DAHC) and channel hot-electron (CHE) stress are compared. are compared.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.292-295
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• 2002

In this work, transient characteristics of NPT(Non Punch Through)-IGBT(Insulated Gate Bipolar Transistor) have been studied with different temperatures analytically. Power losses are caused by heat generated in MIT-IGBT for steady state and transient state conditions. We therefore have focused on the analysis of excess carrier concentration and excess charge injected into N-drift layer with different temperatures and have obtained anode voltage drop during turn-off with lifetime of 2.4[${\mu}$s].

• Journal of Radiation Protection and Research
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• 제1권1호
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• pp.15-21
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• 1976

본 연구는 무단체 Pm-147 의 농도 및 pH 변화에 대하여 여과과정에서 막여과지(膜濾過紙)에 대한 흡착(吸着)상태를 조사하여 무단체 Pm-147의 용액(溶液)상태에 있어서 화학적(化學的)상태 및 흡착(吸着)상태에서의 Pm-147 의 화학적 상태에 관하여 연구하였다. 이와 아울러 방사능(放射能)물질의 담체(擔體)로 사용되는 $Fe(OH)_3$와의 공심(共沈)상태를 연구하였다. 무단체 Pm-147 수용액(水溶液)에서 $Pm^{3+}$ 상태로 족재하며 막(膜)여과지에 의한 여과과정에서 흡착(吸着)이 일어난다. 흡착상태(吸着狀態)는 pH에 따라 여러가지 이온상태로 존재하고 있다. 즉 pH 5.0까지는 $Pm^{3+}$ 상태로 존재하며 $pH5.0{\sim}6.0$까지는 점차로 $Pm(OH)^{2+}$ 상태로 옮아가며 pH 6.0 이상에서는 $Pm(OH)^{2+}$에서 $Pm(OH)_2^+$, $Pm(OH)_3$ 상태로 흡착(吸着)상태로 흡착상태가 이동한다. $Fe^{3+}$와 $Pm^{3+}$의 공심(共沈)은 $F(OH)_3$에 대한 $Pm^{3+}$의 흡착이며 높은 pH 및 Fe 담체(擔體)의 양(量)에 따라 $Pm(OH)^{2+}$ 및 $Pm(OH)_2^+$등의 상태로 나타나고 있다.

• 한국통신학회논문지
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• 제19권11호
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• pp.2067-2080
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• 1994

최근, 디지털 이동 통신 시스템에서, Blind 등기화와 Carrier Recovery의 결합에 관한 관심이 점점 증가하고 있다. 본 논문에서는 변조된 QAM신호를 위한 Blind 등화기와 다양한 Carrier Recovery의 결합한 새로운 수신기를 제시하였다. Godard blind 등화기, Map estimation Costas loop, Generalized Costas loop, Leclert loop, Angular Form loop를 간단히 검토한 후, 등화기와 CR loop의 결합형태를 갖는 두가지 수신기 구조를 제시한다. 몬테 카를로 시뮬레이션 기법을 사용하여, 본 논문에서 제시한 두가지 수신기 구조가 정상상태에서 잘 동작 됨을 확인할 수 있다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.139.2-139.2
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• 2016

Electrons and phonons in chalcogenide-based materials play are important factors in the performance of an optical data storage media and thermoelectric devices. However, the fundamental kinetics of carriers in chalcogenide materials remains controversial, and active debate continues over the mechanism responsible for carrier relaxation. In this study, we investigated ultrafast carrier dynamics in an multilayered $\{Sb(3{\AA})/Te(9{\AA})\}n$ thin film during the transition from the amorphous to the crystalline phase using optical pump terahertz probe spectroscopy (OPTP), which permits the relationship between structural phase transition and optical property transitions to be examined. Using THz-TDS, we demonstrated that optical conductance and carrier concentration change as a function of annealing temperature with a contact-free optical technique. Moreover, we observed that the topological surface state (TSS) affects the degree of enhancement of carrier lifetime, which is closely related to the degree of spin-orbit coupling (SOC). The combination of an optical technique and a proposed carrier relaxation mechanism provides a powerful tool for monitoring TSS and SOC. Consequently, the response of the amorphous phase is dominated by an electron-phonon coupling effect, while that of the crystalline structure is controlled by a Dirac surface state and SOC effects. These results are important for understanding the fundamental physics of phase change materials and for optimizing and designing materials with better performance in optoelectronic devices.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.14-15
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• 2007

Proton irradiation technology was used for improvement of switching characteristics of the PT-IGBT. The proton irradiation was carried out at 5.56 MeV energy from the back side of processed wafers and at 2.39 MeV energy from the front side of the wafers. The on-state and off-state I-V characteristics and switching properties of the device were analyzed and compared with those of un-irradiated device and e-beam irradiated device which was conventional method for minority carrier lifetime reduction. The proton irradiated device by 5.56 MeV energy was superior to e-beam irradiated device for the on-state and off-state I-V characteristics, nevertheless turn-off time of proton irradiated device was superior to that of the e-beam irradiated device.

• 전자공학회논문지A
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• 제30A권11호
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• pp.1-10
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• 1993

A Study on New Digital In this paper, we propose a new Angular Form Carrier Recovery Loop(AFCR loop) for PSK modulation technique. AF CR loop includes detected angle symbol and Multi Level Hardlimiter. Using zero crossing DPLL, we model 1st 2nd AF CR loop, and also derive SCurve. In order to prove steady state operation of AF CR loop, we evaluate performance of this loop by Monte-Carlo and analytical simulation method. We also compare the performance of AF CR loop to that of other loop in terms of acquisition, S-Curve, and RMS jitter. From the comparison result, we verify that the performance of AF CR loop operates well in steady state.

• ETRI Journal
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• 제28권3호
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• pp.275-281
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• 2006

A very simple and efficient scheme for jitter reduction is proposed for a carrier frequency recovery loop using phase differential frequency estimation, which estimates the current frequency offset based on the difference of the average phases of two successive intervals. Analytical and numerical results presented in this paper show that by simply overlapping the observation intervals by half for frequency offset estimations, both the steady-state and transient performances can be improved. The proposed scheme does not require any additional hardware circuitry, but results in improved performance even with reduced complexity.

• 전기의세계
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• 제26권3호
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• pp.73-75
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• 1977

A coupled-mode approach is used to analyze the interaction of the carrier wave in solid-state materials with the external slow electromagnetic wave. A general condition for an active coupling is derived. Gain characteristics is also examined as a function of operating frequency and thermal-to-drift veocity variations.